The present invention relates to an end point detector suitable for manufacture of semiconductor devices and more particularly to an EPD (end point detector) suitable for use in plasma dry etching equipment as one component of semiconductor manufacturing equipment.
An example of the prior art in this field will be described in the following.
FIG. 6 shows a configuration diagram of a conventional end point detector.
In FIG. 6, reference mineral 1 denotes a base, 2 denotes a plasma dry etching equipment, 3 denotes a sensor body (EPD sensor) installed on the base, and 4 denotes a sensor collector barrel mounted to the sensor body 3.
As shown in FIG. 6, the conventional EPD comprises the sensor body (EPD) 3 disposed close to an inspection window, not shown, of the plasma dry etching equipment 2, and the collector barrel 4 formed fixedly to the sensor body. In the EPD 3, a monitor light emitted through the inspection window during etching is guided through the collector barrel 4 into the sensor body 3. The sensor body 3 detects changes in the monitor light due to changes in that part of the material of a work piece undergoing an etching process, and decides the end point of the etching work by the etching equipment based on changes in the monitor light.
As has been described, in order to secure high sensitivity and accuracy, the EPD sensor body needs to be installed close to the etching equipment. The sensor collector barrel is generally made of a resin for its better workability.
However, in the above-mentioned conventional EPD, the inner surface of the sensor collector barrel is affected by ultraviolet rays included in the monitor light or a reactive etching gas that leaks from the etching equipment at periodic dismantling inspection or the like over an extended period of use. Therefore, the monitor light passing through the collector barrel suffers scattering, with the result that the photodetector of the sensor body becomes unable to receive a normal quantity of light.
If, as a result, a deviation or an end point error occurs in etching end point decision, this can lead to discarding of a semiconductor wafer as an etching workpiece, which has become much of a problem.
In the conventional EPD having the collector barrel mounted fixedly to the EPD, if the collector barrel deteriorates as mentioned above, it is necessary to replace the whole EPD, which has been uneconomical and used to lead to reduced durability of the EPD.
An object of the present invention is to eliminate the above problem and provide an end point detector for etching equipment, which is free from deterioration of the EPD sensor collector barrel and excellent in durability.
Another object of the present invention is to provide an end point detector for manufacture of semiconductor devices, which detector is adapted to be able to adjust the quantity of light received.
Yet another object of the present invention is to provide an EPD, which has economical advantages and excellent durability.
According to the present invention, there is provided an end point detector for a plasma-utilized detecting a monitor light to control the operation of an etching process by the etching equipment based on changes in a monitor light emitted by the etching equipment, comprising a sensor body for detecting the monitor light, and a collector barrel for guiding the monitor light from the etching equipment to the sensor body, wherein the collector barrel is detachable from the sensor body.
The collector barrel may be formed of an etch-resistant material that does not react with an etching gas of the etching equipment.
The collector barrel may be formed of either carbon or a metal.
As the metal material mentioned above, aluminum covered on its surface with a layer of aluminum oxide may be used.
The collector barrel may have a shape such that the internal diameter gradually increases from a proximal end thereof as a connection to the sensor body to a distal end thereof.
The end point detector according to the present invention may further comprise a plurality of collector barrels, including the above-mentioned collector barrel. The plurality of collector barrels are selectively detachable from the sensor body, and may be selectively used to adjust the quantity of light received at the sensor body.
The plurality of collector barrels may differ in roughness of the internal circumferential surface.
The plurality of collector barrels may differ in internal diameter.
The plurality of collector barrels may differ in longitudinal length.
At least one of the plurality of collector barrels may increase in internal diameter gradually from a proximal end thereof as a connection to the sensor body to a distal end thereof.
The plurality of collector barrels may include at least two collector barrels with different rates of increase in internal diameter.
Another end point detector according to the present invention for detecting a monitor light to control the operation of an etching process by a plasma-utilized etching equipment based on changes in the monitor light emitted by the etching equipment, comprising a sensor body for detecting the monitor light, and a collector barrel for guiding the monitor light from the etching equipment to the sensor body, wherein the collector barrel is selectively detachable from the sensor body to adjust the quantity of light received at the sensor body.